It seems that there is no simple answer to the question of curing sun damage on a deeper, molecular level, but scientists are well on their way to providing solutions for UV damage. "Although you can't completely turn back the clock and erase sun damage, there are definitely things you can do now that can help to heal your skin and your DNA, and put yourself on the road to recovery," Dr. Bowe clarifies. But unless you wish to spend your life savings on laser treatments, spot-fading serums, and DNA repair enzyme formulas while you wait for science to catch up, you might consider simply slathering on sunscreen or wearing a wide-brim hat instead.
In NHEJ, DNA Ligase IV , a specialized DNA ligase that forms a complex with the cofactor XRCC4 , directly joins the two ends.  To guide accurate repair, NHEJ relies on short homologous sequences called microhomologies present on the single-stranded tails of the DNA ends to be joined. If these overhangs are compatible, repair is usually accurate.     NHEJ can also introduce mutations during repair. Loss of damaged nucleotides at the break site can lead to deletions, and joining of nonmatching termini forms insertions or translocations. NHEJ is especially important before the cell has replicated its DNA, since there is no template available for repair by homologous recombination. There are "backup" NHEJ pathways in higher eukaryotes .  Besides its role as a genome caretaker, NHEJ is required for joining hairpin-capped double-strand breaks induced during V(D)J recombination , the process that generates diversity in B-cell and T-cell receptors in the vertebrate immune system .